Re: LVM question
I hope i can ask a question on top of this one,
what if i have a PV which is configured and in use for a while,
but i found out that i forgot to set the pertition type on LVM.
Can i still change this without data loss or risk?
And if i don't will i face issues of another kind?
On Mon, Apr 20, 2015 at 10:33:13AM +0100, Darac Marjal wrote:
> On Mon, Apr 20, 2015 at 09:26:54AM +0200, Petter Adsen wrote:
> > Is it possible to have two VGs on the same PV?
>
> I don't believe so. The VG is the mapping layer in the LVM stack. It
> maps the LVs to the PVs. If you were to share a PV between VGs, then
> you'd need some way to tell the VGs which parts of the PV they can use
> (letting them battle it out and potentially over-commit the PV is not
> really a good idea). The easiest idea is to split the underlying device
> into multiple PVs (e.g. use partitions).
>
> >
> > If so, how can I make a VG with lots of free space smaller? I'm
> > suspecting that the answer to my first question is "no", since this
> > doesn't seem possible from the man pages.
>
> A quick bit of searching suggests the incantation would be:
> * Boot from a rescue/live disc
> * Activate your VG
> * (You say you've got unallocated space in your VG, so resizing
> filesystems/LVs won't be covered)
> * "lvm pvs" should, at this point, indicate some PFree, which is how
> much you can shrink the PV
> * Run "lvm pvresize /dev/whatever --setphysicalvolumesize 50G"
> (Where /dev/whatever is the PV device and 50G is the new size to
> resize to)
> * Finally, resize the PV's partition appropriately.
>
> At this point, you will have a smaller PV and less unallocated space in
> your VG. You can now create another partition, PV that and add it to a
> second VG.
>
> >
> > Petter
> >
> > --
> > "I'm ionized"
> > "Are you sure?"
> > "I'm positive."
>
>
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